Full Synthetic Oil or Synthetic Blend?

Presentation

Presentation

Well-Known Member
TECHNICAL Contributor
Oct 3, 2006
4,404
Wisconsin - Winnebago Pool chain of lakes
Boat Info
280 Sundancer, Westerbeke MPV generator
Engines
twin 5.0's w/BIII drives
I was just looking at the small cost difference of the relatively new full synthetic merc oil vs the synthetic blend that I have been using.

Does anyone have opinions on the value of converting to the full synthetic oil?

I have listed the prices per quart of the three: full synthetic, blend, and traditional. Sold by the gallon costs are slightly lower.

Mercury MerCruiser Full Synthetic Oil 858087K01 $8.70/quart
Mercury MerCruiser Synthetic Blend Oil 858055K01 $7.28/quart
Mercury MerCruiser Oil 858048K01 $5.80/quart
 
I am thinking of switching from synthetic blend to full synthetic, it is not that much more. Not sure if there is that much more benefit.
 
skolbe said:
I am thinking of switching from synthetic blend to full synthetic, it is not that much more. Not sure if there is that much more benefit.
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Thats the question....any benefit at all ???:huh:
 
I change oil every 30 hours, so I just used the blend.
 
I'm running Royal Purple full syn... works fine. Boattest did a review a while back. Increased mpg and quieter engine. Works for me... Many use Amsoil syn with FC-W...

I change every 100 hours as per the owners manual... even though that is for dino...
 
I'm switching to AMSOIL this year in the boat and the sea doo. About the same cost but a 'better' product, IMO.
 
Out of cutiosity, what weight oil are people using in the boats when they switch to AMSOIL? I don't think AMSOIL offers 25W40 in their product line. Is it the 10W30 or 10W40 that is being used in the boats? I know this topic has been beat to death on this site, so I was wondering if there was something new on the market from AMSOIL. I use the diesel 15W40 in my CUMMINS diesel Dodge 3500 truck and like the product.
 
For $7.10 (5 quarts) difference - I use full Mercury full synthetic and change oil every season approximaetly 60 hours per season.
 
I use 25W40 Synth Blend and change every season.

I use Synthetic Blend due my research I had completed a while ago. Apparently, synth blend does allow you to add normal oil if you needed to. The blend is just that: a blend of synth and non-synth.

So, my thought process is that if I desperately needed to add oil, I would not be as limited.

I do carry extra synth blend on board, but I now have a contigency plan to my contigency plan.

(please correct me if my logic is not correct)
 
I use Amsoil 15w 40. They make a product that is heavy duty marine and diesel. Their product number is: AME04. I have used it in my 02 340 since new and change once a year.
Very happy with this oil. May cost more however its the cheapest insurance I am aware of.
 
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sfergson727 said:
I'm running the Mercury full synthetic oil, having switched over from Mercs synthetic blend last year. I am definitely getting better mpg this year over last. The only thing that has changed is the oil that I am using, so while I traditionally don't believe oil makes much difference, it appears as though it has.

Last year: 3550 RPM, 27.6 mph, 31.1 gph

This year: 3550 RPM, 29.2 mph, 30.6 gph

(Each outing was with full fuel and water, 1 person onboard, which is how I ran the boat last year as well.)

I've checked it on two separate outings to make sure it's not a fluke, and so far it doesn't appear to be.

I'll be using Merc's full synthetic from now until the next latest and greatest comes available.
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Scott,

I have been using full synthetic all this season as well, and I have not really checked mpg compared to last season. The one thing I have noticed is every time I check my oil the oil on the dip stick is clean….. not black, and I like that!
 
I doubt that the oil is the cause of the speed/MPG improvement. After 35 years as an automotive engineer and testing the impact of oil and friction on fuel consumption on engines the change is very small. I mean .1-.2 MPG change, enough to impact fuel economy labels but not enough for the normal consumer to measure. My guess is that something else has changed for the better.
 
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A factor not accounted for in your calculations is the formulation of the fuel. If the manufacturer changed it's formulation from last year to this year it would have a much greater impact on fuel economy.
 
LTD.330 said:
A factor not accounted for in your calculations is the formulation of the fuel. If the manufacturer changed it's formulation from last year to this year it would have a much greater impact on fuel economy.
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The only formulation that would make that much difference is if he used ethanol based fuel last year and ethanol free fuel this year. He stated that it was the same time of the year which means it would have had about the same amout of butane blended in for vapor pressure control. Up north butane is blended in higher percentages during colder months to make the gas more volatile to start easier.

Scott,
Did the full synthetic have the same or lower viscosity rating as your blend?

Also did you shed a few pounds this year versus last that might have "lightened" the load?:smt043
 
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+1. Regardless of the infomercial hype, oil is rarely the solution-and regularly changed oil, regardless of formulation, is rarely the problem. Having said that, out of hubris rather than science, I used full synth last time and will use a blend this time. I change it every season and just don't put enough hours on require the (electron microscopically thin) additional margin of protection.

tbirdvet said:
I doubt that the oil is the cause of the speed/MPG improvement. After 35 years as an automotive engineer and testing the impact of oil and friction on fuel consumption on engines the change is very small. I mean .1-.2 MPG change, enough to impact fuel economy labels but not enough for the normal consumer to measure. My guess is that something else has changed for he better.
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There has been some research that shows better fuel economy with synthetic oil. I believe one of the primary reasons for this is synthetic has a light lubricity than petroleum oils. This higher lubricity reduces friction thus improves fuel economy. In my experience, synthetic oils tend to come in low viscosities which also tends to reduce friction but not as much. Granted, the article below is by a synthetic oil manufacturer, so they may be some bias, but still supports Scott's experience.

http://www.performanceoiltechnology.com/gaugingfueleconomyimprovements.htm
 
sfergson727 said:
I'm running the Mercury full synthetic oil, having switched over from Mercs synthetic blend last year. I am definitely getting better mpg this year over last. The only thing that has changed is the oil that I am using, so while I traditionally don't believe oil makes much difference, it appears as though it has.

Last year: 3550 RPM, 27.6 mph, 31.1 gph

This year: 3550 RPM, 29.2 mph, 30.6 gph

(Each outing was with full fuel and water, 1 person onboard, which is how I ran the boat last year as well.)

I've checked it on two separate outings to make sure it's not a fluke, and so far it doesn't appear to be.

I'll be using Merc's full synthetic from now until the next latest and greatest comes available.
Click to expand...
:smt1013550rpm is 3550rpm. Something was different in order for you to pick up 1.6mph at the same rpm but it wasn't your oil.
 
Presentation said:
I was just looking at the small cost difference of the relatively new full synthetic merc oil vs the synthetic blend that I have been using...Mercury MerCruiser Full Synthetic Oil 858087K01 $8.70/quart...
Click to expand...

Pres,
Where did you find Quicksilver Full Synthetic for this price? I could only find it for $13+ at Amazon.com.
 
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